64940209 has 2 divisors, whose sum is σ = 64940210. Its totient is φ = 64940208.

The previous prime is 64940207. The next prime is 64940243. The reversal of 64940209 is 90204946.

It is an a-pointer prime, because the next prime (64940243) can be obtained adding 64940209 to its sum of digits (34).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63250209 + 1690000 = 7953^2 + 1300^2 .

It is a cyclic number.

It is not a de Polignac number, because 64940209 - 2¹ = 64940207 is a prime.

Together with 64940207, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (64940207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32470104 + 32470105.

It is an arithmetic number, because the mean of its divisors is an integer number (32470105).

Almost surely, 2^64940209 is an apocalyptic number.

It is an amenable number.

64940209 is a deficient number, since it is larger than the sum of its proper divisors (1).

64940209 is an equidigital number, since it uses as much as digits as its factorization.

64940209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 64940209 is about 8058.5488147681. The cubic root of 64940209 is about 401.9492543389.

The spelling of 64940209 in words is "sixty-four million, nine hundred forty thousand, two hundred nine".